The use of conventional switch mode power supplies, or converter circuits, for charging capacitive loads, such as a camera photoflash capacitor, is known. U.S. Pat. No. 6,518,733 to Schenkel et al., entitled “Circuits and Techniques for Capacitor Charging Circuits,” describes various features of such a circuit. For example, a switch control scheme is described in the '733 Patent with which the main converter switch is controlled based on the transformer primary winding current and the secondary winding current. Specifically, the switch on time is controlled in response to the sensed primary winding current and the switch off time is controlled in response to the sensed secondary winding current. The above-referenced patent also describes sensing the converter output voltage from the primary side of the transformer with a comparator in order to determine when the capacitor is charged to the desired level. One-shot circuitry is used to disable the output of the comparator for an interval at the beginning of each off time of the switch since the voltage spikes occurring when the switch shuts off are not indicative of the actual output voltage.